CVE-2026-24037 in horilla
Summary
by MITRE • 01/22/2026
Horilla is a free and open source Human Resource Management System (HRMS). In version 1.4.0, the has_xss() function attempts to block XSS by matching input against a set of regex patterns. However, the regexes are incomplete and context-agnostic, making them easy to bypass. Attackers are able to redirect users to malicious domains, run external JavaScript, and steal CSRF tokens that can be used to craft CSRF attacks against admins. This issue has been fixed in version 1.5.0.
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Analysis
by VulDB Data Team • 01/30/2026
The vulnerability identified as CVE-2026-24037 affects Horilla, a free and open source Human Resource Management System version 1.4.0, presenting a critical cross-site scripting weakness that undermines the application's security posture. This flaw resides within the has_xss() function designed to prevent malicious script injection attempts, demonstrating a fundamental misunderstanding of secure input validation principles. The function employs a set of regular expressions intended to detect and block potential XSS vectors, yet these patterns prove insufficient in their scope and context awareness, creating exploitable gaps in the application's defensive mechanisms.
The technical implementation of this vulnerability stems from the incomplete and context-agnostic nature of the regex patterns used for XSS detection, which directly correlates to CWE-79 - Improper Neutralization of Input During Web Page Generation. These poorly constructed regular expressions fail to account for various encoding techniques, contextual execution environments, and obfuscation methods that attackers commonly employ to circumvent input validation. The regex-based approach represents a flawed security-by-obscurity strategy that relies on a predetermined set of patterns rather than implementing robust, context-sensitive validation mechanisms. Attackers can exploit this weakness by crafting input that bypasses the incomplete regex checks while still executing malicious scripts in the target's browser context.
The operational impact of this vulnerability extends beyond simple script execution, creating a comprehensive attack surface that enables multiple malicious activities. Successful exploitation allows attackers to redirect users to malicious domains, execute external JavaScript code, and steal CSRF tokens from authenticated sessions. This multi-vector capability significantly amplifies the threat potential, as stolen CSRF tokens can be leveraged to perform administrative actions without user consent, potentially leading to complete system compromise. The vulnerability's ability to bypass input validation mechanisms creates persistent security risks for organizations relying on the HRMS platform, particularly those with sensitive employee data and administrative privileges.
The mitigation strategy for CVE-2026-24037 requires immediate deployment of the patched version 1.5.0, which addresses the core regex implementation issues. Organizations should implement comprehensive input validation using context-aware sanitization techniques rather than relying on signature-based regex matching. The fix should incorporate proper HTML entity encoding, content security policy enforcement, and robust output escaping mechanisms that consider the execution context of the data. Additionally, security teams should conduct thorough code reviews to identify similar patterns in other input validation functions and implement proper threat modeling practices that account for various attack vectors including encoding bypasses and context-specific injection points. This vulnerability highlights the importance of following established security frameworks such as OWASP Top Ten and implementing defense-in-depth strategies that go beyond simple regex-based filtering approaches.